1. Field of the Invention
The present invention relates to a solar cell having a structure using a printed circuit board (PCB) and a silicon ball.
2. Discussion of Related Art
A solar cell which is a device for converting energy of light into electricity generates electricity using two types of semiconductors, that is, a P-type semiconductor and an N-type semiconductor. When light is applied to a solar cell, electrons and holes are generated in the solar cell. Charge carriers such as the electrons and the holes move to P and N poles, and a potential difference (photovoltaic power) is generated between the P pole and the N pole. In this case, when a load is connected to the solar cell, current starts flowing, which is called a photoelectric effect.
A silicon solar cell that is generally used in a current solar photovoltaic power generation system has a structure including a silicon wafer substrate, an upper electrode, and a lower electrode. The silicon wafer substrate has a P-N junction between a P-layer and an N-layer. In general, an upper layer of the silicon wafer substrate is formed as the N-layer and a lower layer of the silicon wafer substrate is formed as the P-layer. An upper electrode and an anti-reflection film are formed on a top surface of the N-layer, and a lower electrode is formed on a bottom surface of the P-layer. When light is applied to the solar cell having the structure, charge carriers such as electrons and holes are generated in the solar cell, and among the charge carriers, the electrons move toward an N-type semiconductor and the holes move toward a P-type semiconductor. The charge carriers moving to the N- and P-type semiconductors move to electrodes, and thus current starts flowing.
The solar cell constructed as described above has problems in that a light-receiving area is reduced since light is covered by the upper electrode, and in a solar cell module, efficiency is reduced due to conductive resistance of a ribbon that connects cells. In order to improve photoelectric conversion efficiency, there have been attempts to increase a light-receiving area by reducing a line width of an upper electrode and to reduce reflection loss by reducing a reflectance of a solar cell. In addition to such attempts, various studies have been made to reduce solar cell manufacturing costs.